Bochs is not the only emulator. But Fabrice Bellard wrote more than just qemu, either – tonight I did a quick hack and started booting MirBSD in jslinux. Unmodified. Of course, there are still things to change before this goes into userspace, and the bootloader wants to be ported to ECMAscript as well, but… I got some dmesg(8)!
Feel free to call me crazy now. Anyway, more on this as time and legalese permits. This was a can-do test in about 2 hours of work, only.